Welding and plasma arc torches are widely used in the welding, cutting and marking of materials. A plasma torch generally includes an electrode and a nozzle having a central exit orifice mounted within a torch body, electrical connections, passages for cooling, passages for arc control fluids (e.g., plasma gas), and a power supply. Optionally, a swirl ring is employed to control fluid flow patterns in the plasma chamber formed between the electrode and nozzle. The torch produces a plasma arc, a constricted ionized jet of a gas with high temperature and high momentum. Gases used in the torch can be non-reactive (e.g., argon or nitrogen) or reactive (e.g., oxygen or air). In operation, a pilot arc is first generated between the electrode (cathode) and the nozzle (anode). Generation of the pilot arc can be by means of a high frequency, high voltage signal coupled to a DC power supply and the torch or any of a variety of contact starting methods.
A torch assembly includes one or more leads connecting the torch to the power supply to provide the torch with electrical current and fluid. A similar configuration can be used with a welding apparatus. The engagement of the lead(s) to the power supply should be rugged to handle the stress and/or the strain placed on the lead as it is manipulated to place the plasma arc torch or welding torch in a position to cut, mark, or weld a workpiece. The lead(s) used to connect the torch to the power supply can be a single integral lead having a fluid hose, for example, a gas hose located in the middle of the lead and electrical conductors and fillers arranged symmetrically around the gas hose.
Plasma and welding equipment is comprised of two main components, the torch assembly and the power supply assembly. The torch is usually affixed to the power supply using one of two methods. In the first method, the torch is plumbed inside the unit and can only be changed by using a tool to enter the power supply. In the second method, the torch is attached to the power supply via a detachable connector. A detachable connector offers several advantages. First, it is simple to exchange hand and machine style torches. Second, it is easy to repair a damaged torch. Third, it may be more convenient to store a detached torch separate from the power supply.
Existing connections for connecting leads to the power supply can have any of several limitations. Some lead connections require large access areas which impact power supply size. Certain connectors must be visible to enable engagement and/or disengagement, which impacts lead placement, space, can necessitate lighting and can increase the time required to engage and disengage the lead connectors. Other connectors require the operator to use two hands to complete the engagement and/or disengagement. Adequate space around the power supply and the leads must be available to enable two hands to access the connection. Some known connections require use of one or more tools to enable engagement and/or disengagement. The use of the tool can be time consuming, the tool can be easily misplaced, and space must be available on the power supply and/or adjacent the connector to accommodate the tool. Threaded connector fittings can be incorrectly installed and tightened causing wear and/or leaking. Certain connectors and/or leads leak after multiple or frequent engagements and disengagements. Previous lead connectors required multiple wrench connections, which is time consuming. Replacement of the lead set in the field is challenging and time consuming due to the limitations of these prior systems.
Existing designs in torch connector technology often rely upon a nut to couple the torch plug onto the power supply socket. Nuts have the advantage of being easy to make, easy to use, while having a high retention force. The disadvantage of the nut is that it takes some time to thread and unthread, may require two hands, and adds bulk to the connector. A less common alternative connector design utilizes common pneumatic and electrical components. This has the advantage of using off the shelf components. A disadvantage of this coupler is that it is unnecessarily bulky, awkward to disconnect, and expensive to mold.
Another disadvantage of current torch connector designs is that the mating structure protrudes from the power supply. Designs incorporating a nut to couple the torch plug onto the power supply requires a threaded socket extending from the power supply. Such designs are not aesthetically pleasing and create additional protrusions from a power supply. Outwardly protruding sockets are also susceptible to damage, resulting in expensive repairs. Moreover, in order to be coupled, a nut must inherently be larger than a socket, requiring that the attached torch plug create an even larger footprint than the socket alone. Also, the nuts require sufficient clearance around the circumference to be hand threaded onto the socket. The space available to rotate a nut is increasingly limited as the size of power supplies become smaller and smaller.